Fei Yuan MD, Presenter: Nothing to Disclose

Objective: The purpose of our study was to evaluate the accuracy of MR myelography (MRM) in depicting lumbosacral meningeal cysts compared with conventional MRI

Materials and MethodsThe history, MRI and MR myelography(MRM) of the lumbosacral spine were reviewed retrospectively in 14 patients with surgically-proven arachnoid cysts. All had a history of leg weakness of 3 months to 5 years duration, four of incontinence and seven of numbness in the legs. There was a history of lumbar procedure in one patient, other patients had no history of surgery or trauma.All MR imaging was performed with a 1.5-T superconducting system. The MRM images were obtained using a 3D/FSE T2-weighted pulse sequence. An inversion pulse was applied to completely suppress the fat signal. In addition, presaturation superior/inferior, flow compensation and no-phase-wrap option were used to minimize artifacts. The image data were then transferred to a workstation (ADW4.0, GE Medical Systems) for three-dimensional myelographic image reconstruction with a maximum intensity projection algorithm in varied views.

Results :One cases were Type IA, 6 cases Type IB and 7 cases Type II of extradural meningeal cyst. 13 extradural meningeal cysts were seen on conventional MRI as opposed to 38 cysts on MRM.

Conclusion The sensitivity and accuracy of MRM for extradural meningeal cysts were higher than conventional MRI with its excellent definition of the thecal sac, nerve roots and nerve sheath. It can define the cyst type by visually demonstrating the location, shape, size, number of cysts and the communication between the cyst and subarachnid space as well as the track of nerve roots within the cysts.

Yuan, F, Evaluation of the Role of Magnetic Resonance Myelography in Spinal Extradural Meningeal Cyst.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4409432.html